This disclosure relates generally to vascular access devices and methods, including catheter assemblies and devices used with catheter assemblies. Generally, vascular access devices are used for communicating fluid with the vascular system of patients. For example, catheters are used for infusing fluid, such as saline solution, various medicaments, and/or total parenteral nutrition, into a patient, withdrawing blood from a patient, and/or monitoring various parameters of the patient's vascular system.
Intravenous (IV) catheter assemblies are among the various types of vascular access devices and over-the-needle peripheral IV catheters are a common IV catheter configuration. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the inner surface of the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitate insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin. The catheter and introducer needle are generally inserted at a shallow angle through the patient's skin into a blood vessel.
In order to verify proper placement of the needle and/or catheter in the blood vessel, the clinician generally confirms that there is “flashback” of blood in a flashback chamber, which is generally associated with a needle assembly. Once proper placement of the distal tip of the catheter into the blood vessel is confirmed, the clinician may apply pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal of the introducer needle and the catheter. This finger pressure occludes the vessel, minimizing further blood flow through the introducer needle and the catheter.
The clinician may then withdraw the introducer needle from the catheter. The introducer needle may be withdrawn into a needle tip shield that covers the needle tip and prevents accidental needle sticks. In general, a needle tip shield includes a housing, a sleeve, or other similar device that is designed such that when the needle is withdrawn from the patient, the needle tip will be trapped/captured within the needle tip shield. The purpose of the needle tip shield is to house the tip of the needle in a secure location, thereby reducing the possibility of needle sticks when the needle and needle tip shield are separated properly from the catheter, which is left in place to provide intravenous access to the patient.
The separation of the needle assembly from the catheter portions of the catheter assembly presents numerous potential hazards to the clinicians and others in the area. As indicated above, there is a risk of accidental needle sticks if the needle tip is not secured properly in a needle tip shield. Additionally, between the time that the needle assembly is separated from the catheter portions and the time that the catheter portions are coupled to another medical device, such as an IV drip bag or pump machine, or are otherwise closed off, there is a risk that blood will exit from the catheter under the pressure of the patient's vascular system. Clinicians are very skilled at occluding the blood vessel through manual pressure and at the transition between removal of the needle assembly and closing the patient's vascular system through one or more of these techniques. Nevertheless, there is a risk that some blood may exit the system even in a perfect transition. For example, blood may follow the needle tip as the needle is withdrawn from the catheter and may splatter, splash, drip, or otherwise exit the proximal end of the catheter. Any blood flow from the proximal end of the catheter risks exposure to clinicians and is to be avoided.
The problem of unexpected and/or uncontrolled blood exposure during removal of the needle from the catheter is not new. Prior attempts to address this problem have universally relied upon some form of mechanical intervention to block fluid flow. For example, some prior systems have implemented a septum in the catheter hub surrounding the needle tip in an effort to create a closed system in the catheter. Other systems employ other modifications of the conventional catheter assembly to slow or limit blood flow in unintended manners, all of which include some mechanical means of restricting blood flow. While such mechanical solutions are effective to some degree, they can be complex and costly to manufacture. Additionally, such mechanical solutions often add energy to the system, such as the energy required to pull the needle through the septum. The added energy may result in splattering whatever blood does make it through the mechanical barrier. While certainly an improvement over systems without such mechanical blood flow restriction means, many, if not all, of the mechanical blockage systems have inherent leakages either through the design failing to create a perfect seal or through the operation of the mechanical system creating leaks through time delays. Accordingly, the problem of unexpected and/or uncontrolled blood exposure when introducer needles are removed from catheter assemblies remains to be solved. The present disclosure presents systems and methods to significantly limit and/or prevent such blood exposure.